Apparatus to weld a wrapping sheet to the core of a warpped roll-like article

ABSTRACT

An apparatus for attaching a plastic wrapping sheet to a composite product formed of a plastic core tube having a web-shaped material wrapped therearound, the plastic wrapping sheet surrounding the composite product so that an end portion extends beyond an end of the composite product, the apparatus including twin closing yokes which are movable towards one another to gather the end portion together, a cylindrical welding head for welding the gathered end portion to the end of the core tube, and a rotatable cutting bead for removing free excess plastic wrapping sheet from within the core tube.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns an apparatus for use in plastics sheetwrapping of web-shaped material rolled up on a plastics-containing coretube having substantially the same length as the width of the web-shapedmaterial, the apparatus including closing parts which are adapted togrip and gather the excess plastics sheet parts which extend beyond therolled-up web-shaped material at at least one end.

2. The Prior Art

Owing to considerations of space and to facilitate handling of theweb-shaped material, core tubes having substantially the same length asthe width of the rolled-up web-shaped material are used today. So far,the end closing of the plastics sheet package around the web-shapedmaterial has been made manually in practice by taping, plugging andsubsequent fixing with staples, respectively, interiorly in the coretube. These methods are difficult and cumbersome to perform and provideno real certainty that the package will be hermetically tight. Theconsequence is therefore frequently transport damage, in particular incase of wrapped web-shaped material, such as carpet materials which areplaced in their full length on the platform of a truck, where dirt andwater are sucked up at the tailboard during driving. A tight end closureis therefore absolutely necessary. Heavy web-shaped materials, such ascarpet materials, where a roll can weigh up to 600 to 700kg, also makeparticularly great requirements with respect to a strong end closurewhich remains tight with certainty during transport and handling, wherethe tube frequently "sinks" into the material and thus subjects the endclosure to a great load.

GB 2 043 021 discloses an apparatus of the type mentioned in the openingparagraph. However, in this apparatus it is a requirement that the coretube is considerably longer than the width of the rolled-up, web-shapedmaterial for the provision of an asserted tight end closure by heatfusion. However, the apparatus cannot be used commercially in practiceowing to the protruding core tube which occupies unacceptably much spaceduring storage and transport.

Thus, so far it has not been possible to obtain both a tight package,which is important to avoid ingress of dust, dirt and moisture, inparticular during transport on the platform of trucks, and a wrappingmethod which leaves the interior of the tube freely accessible forfork-lift trucks having rods in connection with wrapping of rolled-up,web-shaped material on core tubes which have substantially the samelength as the width of the web-shaped material.

Finally, it should be mentioned that the manual closing does not enabledirect recycling owing to the different materials materials used (tape,plug and staples.

SUMMARY OF THE INVENTION

The apparatus of the present invention is characterized in that itincludes welding means which are adapted to weld gathered plastics sheetmaterial parts along the annular end face on the adjacent end of thecore tube. This ensures that a tight and strong package is provided withcertainty, while the interior of the tube is freely accessible to carpetrods, forks on fork-lift trucks, etc.

In use, the closing parts of the apparatus are joined around the excessplastics sheet parts which are subsequently kept together at the end ofthe core tube with or without engagement of the closing parts. Thewelding head is then driven forwards, and the plastics sheet parts arewelded to the end face of the core tube.

The invention can provide the advantage that the tube appears withoutexcess plastics sheet parts, while a neat end closure is obtained.

The invention may be used to special advantage when both core tube andpackage are made of the same plastics material, e.g., polyethylene,which simplifies the recycling process considerably.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be explained more fully below with reference to thedrawing, in which

FIG. 1 is a lateral view of an apparatus according to the inventioncontaining a web-shaped material, such as a carpet, rolled up on a coretube,

FIG. 2 is an end view of the same,

FIG. 3 is a partially sectional, enlarged view of the plastics sheetwrapped, rolled-up, web-shaped material after welding on the end face ofthe core tube, with the ultrasound head of the apparatus being movedaway,

FIG. 4 is a view of the same after welding on the end face of the coretube, with the cutting head of the apparatus being moved away,

FIG. 5 is a sectional view of an ultrasound head with a cone mounted infront, and

FIG. 6 is a lateral view of knives for severing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The apparatus 30 shown in FIG. 1 for use in plastics sheet wrapping ofrolled-up, web-shaped material 1 on a core tube 2 comprises a frame 3 onwhich a vertically slidable lifting table 4 containing two rollers 5, 6is mounted. The rollers 5,6 are rotatable by means of a motor (notshown). The rollers 5, 6 moreover comprise holding arms 7 which are usedfor guiding the web-shaped material 1 into position and during tippingof the web-shaped material 1. The holding arms are shown in differentpositions in FIG. 2.

The frame 3 moreover mounts two horizontally slidable carriages 8, 9, oneach of which two V-shaped closing yokes 10, 11, a welding head 12 and acutting head 13 are mounted.

The closing yokes 10, 11 are movable vertically in slide guides 21 sothat, seen from the end, they form an opening in the shape of aparallelogram 16 whose area may be made larger or smaller by moving theclosing yokes 10, 11 toward or away from each other. In FIG. 2, theclosing yokes 10, 11 are shown in the open position in solid line and inthe closed position in broken line.

The ultrasonic welding head 12, which is shown in FIG. 3, is cylindricalwith a circular cross-section and has an obliquely bevelled engagementface 14, which is adapted to engage the plastics sheet material alongthe internal 17 or external 18 annular edge of the core tube at the endface 22 of the core tube during welding. The welding head is slidablevertically. In addition, it is movable horizontally so that it may bemoved toward and away from the core tube.

FIG. 5 shows an embodiment in which a cone 40 is mounted in front of theultrasonic welding head 39, and this cone 40 positions the welding headwith respect to the core tube 2 when the cone is driven into the coretube 2. The cone 40 may be mounted such that it can slide with respectto the welding head 12 via guides 38. Hereby, after positioning, it ispossible to advance the welding head 12 in a direction toward the coretube 2, while the cone 40 is kept stationary within the core tube.

Like the welding heads 12, the cutting means 13 may be moved verticallyas well as horizontally. Further, the cutting means may be moved aroundthe end edge of the core tube. In a particularly expedient embodiment,as shown in FIG. 4, the cutting means may be shaped as a turning saw 13for cutting off excess, free plastics sheet material within the coretube after welding. The cutting means may also be provided as acutting/milling head or knives which cut off the free plastics sheetmaterial directly around the end face 22 of the core tube.

It is shown in FIG. 6 how two knives 41 are mounted behind a cone 42which positions the knife device with respect to the core tube 2. Theknife device 43 is constructed such that the knives 41 are movedradially outwards when the shaft 45 of a motor (not shown) rotates inone direction of rotation, and radially inwards when the shaft 45rotates in the other direction of rotation.

For the shown closing of the end on the plastics sheet wrapped,rolled-up, web-shaped material, the roll 1 is placed on the rollers 5, 6and is guided into position via the holding arms 6, 7. Then the liftingtable 4 is raised/lowered to position the core tube 2 of the roll inalignment with the welding heads 12 via laser equipment (not shown).Then the carriages 8, 9 are run inwards toward their respective sides ofthe roll.

The rollers 5, 6 are subsequently caused to rotate, whereby also theroll 1 rotates. Simultaneously, the closing yokes 10, 11 are movedtogether around the excess plastics sheet parts at the ends, the closingyokes retaining the plastics sheet parts during continued rotation ofthe roll. In other embodiments (not shown), the closing yokes 10, 11 andthereby the excess plastics sheet parts can be rotated so that theplastics sheet parts are kept together twisted in a desired manner afterthe closing yokes have moved away.

Then the twisted plastics sheet parts are welded together by means ofwelding equipment (not shown), and the excess plastics sheet parts areremoved.

Then the welding heads 12 are advanced and urge the plastics sheet partstwisted and welded together into the ends of the core tube 2, and theplastics sheet is is welded by means of ultrasound to the annularinwardly facing edge area 17 on the end face of the core tube 2.

Welding takes place in that the welding head 12, which is substantiallyin the shape of a truncated cone, is caused to oscillate withhigh-frequency oscillations, preferably 10 to 40 kHz, whereby theplastics sheet is welded to the end face of the core tube, see FIGS. 3and 4. After welding, a complete plastics sheet weld will be provided onthe end face. In connection with wrapping of carpet material the coretube normally has an outer diameter of 110 mm, and the dimensions of themandrel 12 therefore correspond to this.

Then the welding heads 12 return, and the turning saw 13 is passed intothe core tube 2 and cuts off the excess plastics sheet parts.

When the knives 41 are to be used, the knife device 43 is inserted intothe core tube 2, while the knives 41 are displaced radially inwards. Themotor is then caused to rotate in one direction of rotation, and theknives 41 will be displaced radially outwards and simultaneously cut offexcess, free plastics sheet material within the core tube 2. Aftercutting, the motor is caused to rotate the shaft 45 in the otherdirection of rotation, and the knives 41 will therefore be displacedradially inwards so that the knife device 43 can then be moved out ofthe core tube 2.

A hook device 43 may be placed in front of the knife device 43, the hookdevice carrying along the excess plastics sheet material when the knifedevice 43 is moved out of the core tube.

Finally, the excess plastics material is sucked away via a centralopening 23 in the turning saw 13, which then returns. Lastly, thecarriages 8, 9 return, and the lifting table 4 is run to the startingposition, following which the roll 1 is tipped out of the apparatusduring rotation of the holding arms 7.

FIG. 4 shows another embodiment of the wrapping. In this case, the weld18 is made on the outer edge 1B of the end face 22 of the core tube, andthe cutting head 13 is being moved away from the core tube 2.

Most frequently, the core tube 2 comprises a plastics tube, but in otherembodiments it may be formed by, e.g., a cardboard tube having an innerplastics coat or a cardboard tube having a plastics bushing at the end.

Many modifications are possible without departing from the actual ideaof the invention. In the embodiment shown, the closing yokes areV-shaped. However, also more than two closing yokes shaped as, e.g.,straight lines or curves are conceivable.

I claim:
 1. An apparatus for attaching a plastic sheet to a compositeproduct formed of an elongated core tube comprised of a plastic materialand a web-shaped material wrapped around the elongated core tube, saidcore tube having a length which is substantially equal to a width of theweb-shaped material and defining first and second ends in substantialalignment with respective opposite first and second side edges of theweb-shaped material, the plastic sheet including a first end portionwhich extends beyond the first end of the core tube and first side edgeof the web-shaped material, said apparatus comprising closing means forgripping and gathering the first end portion of the plastic sheet,welding means for welding said gathered first end portion of saidplastic sheet to said first end of said core tube, said welding meansincluding a welding head having an engagement face for engaging theplastic sheet material along one of an inner and outer annular edge ofthe first end of the core tube and cutting means comprising a millinghead mounted to be axially slidable in an inward direction toward aninterior of the core tube for removing free excess plastic sheet partsafter welding.
 2. An apparatus according to claim 1, wherein saidcutting means comprise a shaft and a knife device having knives radiallymovable outwardly when the shaft is rotated in one direction of rotationand radially inwardly when the shaft is rotated in an oppositedirection.
 3. An apparatus according to claim 1, including engagementmeans for engaging the wrapped web-shaped material, and wherein one ofthe engagement means and the closing means provide a relative turningmovement between said excess plastic sheet parts and the wrappedrolled-up web-shaped material prior to welding.
 4. An apparatusaccording to claim 2, wherein the engagement means comprise supportingrollers which are positioned in parallel with a longitudinal axis of thecore tube.
 5. An apparatus according to claim 1, wherein the closingmeans comprise engagement faces directed toward each other and areretained slidably so that, during movement of the parts in a directiontoward each other, the engagement faces define an opening to receive theexcess plastic sheet parts.
 6. An apparatus according to claim 1,wherein the closing means comprise V-shaped yokes.
 7. Use of theapparatus according to claim 1 for plastics sheet wrapping of rolled-upcarpet materials.
 8. Use of the apparatus according to claim 1 forpolyethylene sheet wrapping of web-shaped material rolled up on a coretube of polyethylene.
 9. An apparatus according to claim 1, wherein saidwelding head comprises a cylindrical ultrasonic welding head.
 10. Anapparatus according to claim 9, wherein said engagement face of saidcylindrical ultrasonic welding head is obliquely beveled.
 11. Acombination of:(a) a composite product formed of an elongated core tubecomprised of a plastic material and a web-shaped material wrapped aroundsaid elongated core tube, said core tube having a length substantiallyequal to a width of said web-shaped material and defining opposite firstand second ends in substantial alignment with respective opposite firstand second side edges of said web-shaped material, and (b) an apparatusfor attaching a plastic sheet which is wrapped around said compositeproduct, such that a first end portion of the plastic sheet extendsbeyond said first end of said core tube, said apparatus comprisingclosing means for gripping and gathering said first end portion of saidplastic sheet, and welding means for welding said gathered first endportion of said plastic sheet to said first end of said core tube, saidwelding means including a welding head having an engagement face forengaging the plastic sheet material along one of an inner and outerannular edge of the first end of the core tube, (c) an apparatus whereincutting means comprise a milling head mounted to be axially slidable inan inward direction toward an interior of the core tube for removingfree excess plastic sheet parts after welding.